An observational study published in the journal Diabetes Care is calling into question recent Dietary Guidelines for Americans that recommend adults, and especially diabetics, should consume no more than two-thirds of a teaspoon of salt per day, or about 1.5 grams. Australian researchers followed 638 participants with longstanding type 2 diabetes. Roughly half the patients were obese. At the onset of the study, doctors measured the daily amount of sodium in the patients’ urine — a close reflection of the quantity ingested — and found the average amount to be 4.2 grams of sodium per day. After following the study subjects for over a decade, it was shown that for every additional 2.3 grams of sodium measured in their urine, patients had a reduced their mortality risk of 28 percent — a startling and counter-intuitive outcome.
Although researchers accounted for kidney disease, age and other relevant factors in the study, they nevertheless found that patients with the lowest urine sodium levels were on average sicker and older.
ACSH staff agreed that the message here is clear: It is wrong to assume that a sodium-restricted diet is good for everyone. “Some people may benefit by limiting their salt intake, some may see no effect at all while others, like the diabetics in this study, may actually be harmed by such a recommendation,” says ACSH’s Dr. Gilbert Ross. “That being said, this is merely one study, and given the surprising results, will certainly bear repeating before inscribing it as a medical dictum.”
ACSH staffer Jonathan Leaf chimes in: “This just goes to show that aggressive public health campaigns against salt, like those most recently launched by the NYC Health Department, may be misguided and yield unintended consequences.”
“Intuitively, you would think diabetics would benefit from a low-sodium diet, but preliminary data from this study suggests that this may not necessarily be the case,” adds ACSH’s Dr. Elizabeth Whelan.
To try to resolve the controversy, Dr. Michael H. Alderman of the Albert Einstein College of Medicine in New York believes a clinical trial comparing people advised to eat less sodium to those maintaining their usual salt regimen is necessary. “It is surely safer, and probably cheaper than to ask 300 million Americans to reduce their sodium intake because of the hope that it will actually extend or improve life,” he says.